Intranasal delivery of cardiovascular agents: an innovative approach to cardiovascular pharmacotherapy

Intranasal Delivery of Carvedilol- and Quercetin-Encapsulated Cationic Nanoliposomes for Cardiovascular Targeting: Formulation and In Vitro and Ex Vivo Studies

Carvedilol (CVD), an adrenoreceptor blocker, is a hydrophobic Biopharmaceutics Classification System class II drug with poor oral bioavailability due to which frequent dosing is essential to attain pharmacological effects. Quercetin (QC), a polyphenolic compound, is a potent natural antioxidant, but its oral dosing is restricted due to poor aqueous solubility and low oral bioavailability. To overcome the common limitations of both drugs and to attain synergistic cardioprotective effects, we formulated CVD- and QC-encapsulated cationic nanoliposomes (NLPs) in situ gel (CVD/QC-L.O.F.) for intranasal administration. We designed CVD- and QC-loaded cationic nanoliposomal (NLPs) in situ gel (CVD/QC-L.O.F.) for intranasal administration. In vitro drug release studies of CVD/QC-L.O.F. (16.25%) exhibited 18.78 ± 0.57% of QC release and 91.38 ± 0.93% of CVD release for 120 h. Ex vivo nasal permeation studies of CVD/QC-L.O.F. demonstrated better permeation of QC (within 96 h), i.e., 75.09% compared to in vitro drug release, whereas CVD permeates within 48 h, indicating the better interaction between cationic NLPs and the negatively charged biological membrane. The developed nasal gel showed a sufficient mucoadhesive property, good spreadability, higher firmness, consistency, and cohesiveness, indicating suitability for membrane application and intranasal administration. CVD-NLPs, QC-NLPs, and CVD/QC-NLPs were evaluated for in vitro cytotoxicity, in vitro ROS-induced cell viability assessment, and a cellular uptake study using H9c2 rat cardiomyocytes. The highest in vitro cellular uptake of CVD/QC-cationic NLPs by H9c2 cells implies the benefit of QC loading within the CVD nanoliposomal carrier system and gives evidence for better interaction of NLPs carrying positive charges with the negatively charged biological cells. The in vitro H2O2-induced oxidative stress cell viability assessment of H9c2 cells established the intracellular antioxidant activity and cardioprotective effect of CVD/QC-cationic NLPs with low cytotoxicity. These findings suggest the potential of cationic NLPs as a suitable drug delivery carrier for CVD and QC combination for the intranasal route in the treatment of various cardiovascular diseases like hypertension, angina pectoris, etc. and for treating neurodegenerative disorders.

Nose-to-Heart Approach: Unveiling an Alternative Route of Acute Treatment

Intranasal (IN) administration has emerged as a novel approach for rapid systemic absorption, with potential applicability in the management of acute cardiovascular events. This review explores the evolution of IN cardiovascular pharmacotherapy, emphasizing its potential in achieving systemic effects and bypassing the first-pass metabolism associated with oral administration. The extensive vascularization of nasal mucosa and a porous endothelial basement membrane facilitate efficient drug absorption into the bloodstream. The IN route ensures a critical swift onset of action, which allows self-administration in at-home settings. For instance, etripamil nasal spray, a first-in-class formulation, exemplifies the therapeutic potential of this approach in the treatment of spontaneous supraventricular tachycardia. The review critically assesses studies on IN formulations for angina, acute myocardial infarction, hypertensive episodes, and cardiac arrhythmias. Preclinical evaluations of beta-blockers, calcium-channel blockers, and antianginal drugs demonstrate the feasibility of IN administration for acute cardiovascular events. A small number of clinical trials have revealed promising results, emphasizing the superiority of IN drug delivery over oral administration in terms of bioavailability and onset of action. Unambiguously, the limited clinical trials and patient enrollment pose challenges in generalizing experimental outcomes. However, the nose-to-heart approach has clinical potential.

A Novel Calcium Channel Blocker: Etripamil: What is the Future of Intranasal Drug Delivery in the Treatment of Cardiac Arrhythmias?

Symptomatic paroxysmal cardiac arrhythmias are common cardiac conditions that lead to a decreased quality of life, increased healthcare costs, and significant morbidity. Many cardiac arrhythmias increase in frequency with age, and as the elderly population continues to increase, so will the incidence and prevalence of cardiac arrhythmias. The long-term treatment options for patients with paroxysmal arrhythmias include ablation procedures and daily oral antiarrhythmics. Acute management entails vagal maneuvers, intravenous antiarrhythmics, and synchronized cardioversion. However, there are limited treatment options for patients with less frequent and less severe arrhythmias, ablation refractory disease, or who are poor candidates for ablative procedures, For abortive therapy, oral anti-arrhythmic medications are ineffective due to their slow onset of action and intravenous medications require treatment at an acute care facility, which is both costly and stressful to the patient. Etripamil is a novel intranasal non-dihydropyridine calcium channel blocker that has begun phase III clinical trials for the treatment of paroxysmal supraventricular tachycardias. Due to its intranasal mode of delivery, etripamil has a rapid onset of action, and could feasibly be administered by the patient themselves. Clinical phase II trials of etripamil in moderate to high doses demonstrated efficacy comparable to the standard of care, and took an average of 3 minutes from drug administration to conversion to sinus rhythm. In this article, we have conducted an extensive literature review of intranasal drug delivery, calcium channel blockers, and etripamil, to discuss the future possibilities of using this new medication.

Intranasal drug delivery: opportunities and toxicologic challenges during drug development

Over the past 10 years, the interest in intranasal drug delivery in pharmaceutical R&D has increased. This review article summarises information on intranasal administration for local and systemic delivery, as well as for CNS indications. Nasal delivery offers many advantages over standard systemic delivery systems, such as its non-invasive character, a fast onset of action and in many cases reduced side effects due to a more targeted delivery. There are still formulation limitations and toxicological aspects to be optimised. Intranasal drug delivery in the field of drug development is an interesting delivery route for the treatment of neurological disorders. Systemic approaches often fail to efficiently supply the CNS with drugs. This review paper describes the anatomical, histological and physiological basis and summarises currently approved drugs for administration via intranasal delivery. Further, the review focuses on toxicological considerations of intranasally applied compounds and discusses formulation aspects that need to be considered for drug development.

Activity of Multidrug Resistance-Associated Proteins 1-5 (MRP1-5) in the RPMI 2650 Cell Line and Explants of Human Nasal Turbinate

The profound influence of ATP-binding cassette (ABC) transporters on the disposition of numerous drugs has led to increased interest in characterizing their expression profiles in various epithelial and endothelial barriers. The present work examined the presence and functional activity of five ABC efflux proteins, i.e., MRP 1-5, in freshly isolated human nasal epithelial cells and two in vitro models based on the human RPMI 2650 cell line. To evaluate the expression patterns of MRP1, MRP2, MRP3, MRP4, and MRP5 at the mRNA and protein levels in the ex vivo model and the differently cultured RPMI 2650 cells, reverse transcriptase polymerase chain reaction (RT-PCR), Western blot analysis, and indirect immunofluorescence staining were used. The functionality of the MRP transporters in the three models was assessed using efflux experiments and accumulation assays with the respective substrates and inhibitors. The mRNA and protein expression of all selected ABC transporters was detected in excised human nasal mucosa as well as in the corresponding cell culture models. Moreover, the functional expression of the MRP transport proteins was demonstrated in the three models for the first time. Therefore, the potential impact of multidrug resistance-associated proteins 1-5 on drug disposition after intranasal administration may be taken into consideration for future developments. The specimens of human nasal turbinate exhibited slightly lower efflux capacities of MRP1, MRP3, and MRP5 in relation to the submerged and ALI-cultured RPMI 2650 cells, but showed a promising comparability to both in vitro models concerning the activity of MRP2 and MRP4. In this regard, the different RPMI 2650 cell culture models will be able to provide useful experimental data in the preclinical phase to estimate the interaction of particular efflux transporters with drug candidates for nasal application.

Drug delivery systems, CNS protection, and the blood brain barrier

Present review highlights various drug delivery systems used for delivery of pharmaceutical agents mainly antibiotics, antineoplastic agents, neuropeptides, and other therapeutic substances through the endothelial capillaries (BBB) for CNS therapeutics. In addition, the use of ultrasound in delivery of therapeutic agents/biomolecules such as proline rich peptides, prodrugs, radiopharmaceuticals, proteins, immunoglobulins, and chimeric peptides to the target sites in deep tissue locations inside tumor sites of brain has been explained. In addition, therapeutic applications of various types of nanoparticles such as chitosan based nanomers, dendrimers, carbon nanotubes, niosomes, beta cyclodextrin carriers, cholesterol mediated cationic solid lipid nanoparticles, colloidal drug carriers, liposomes, and micelles have been discussed with their recent advancements. Emphasis has been given on the need of physiological and therapeutic optimization of existing drug delivery methods and their carriers to deliver therapeutic amount of drug into the brain for treatment of various neurological diseases and disorders. Further, strong recommendations are being made to develop nanosized drug carriers/vehicles and noninvasive therapeutic alternatives of conventional methods for better therapeutics of CNS related diseases. Hence, there is an urgent need to design nontoxic biocompatible drugs and develop noninvasive delivery methods to check posttreatment clinical fatalities in neuropatients which occur due to existing highly toxic invasive drugs and treatment methods.

Development, optimization and in vitro evaluation of alginate mucoadhesive microspheres of carvedilol for nasal delivery

The present research work was aimed at development and optimization of alginate mucoadhesive microspheres of carvedilol for nasal delivery to avoid first pass metabolism and to improve the therapeutic efficacy in the treatment of hypertension and angina pectoris. The microspheres were prepared by a water-in-oil (w/o) emulsification technique. A 2(3) factorial design was employed with drug : polymer ratio, calcium chloride concentration and cross-linking time as independent variables while particle size of the microspheres and in vitro mucoadhesion were the dependent variables. Regression analysis was performed to identify the best formulation conditions. Particle size was analysed by dynamic laser light diffraction technique and found to be in the range of 26.36-54.32 microm, which is favourable for intranasal absorption. The shape and surface characteristics were determined by scanning electron microscopy (SEM) which depicted the spherical nature and nearly smooth surfaces of the microspheres. The percentage encapsulation efficiency was found to be in the range between 36.62-56.18. In vitro mucoadhesion was performed by adhesion number using sheep nasal mucosa and was observed in a range from 69.25-85.28. Differential scanning calorimetry and X-ray diffraction results indicated a molecular level dispersion of carvedilol in the microspheres. In vitro release studies in pH 6.2 phosphate buffer indicated non-Fickian or anomalous type of transport for the release of carvedilol from the microspheres.

Intranasal delivery: physicochemical and therapeutic aspects

Interest in intranasal (IN) administration as a non-invasive route for drug delivery continues to grow rapidly. The nasal mucosa offers numerous benefits as a target issue for drug delivery, such as a large surface area for delivery, rapid drug onset, potential for central nervous system delivery, and no first-pass metabolism. A wide variety of therapeutic compounds can be delivered IN, including relatively large molecules such as peptides and proteins, particularly in the presence of permeation enhancers. The current review provides an in-depth discussion of therapeutic aspects of IN delivery including consideration of the intended indication, regimen, and patient population, as well as physicochemical properties of the drug itself. Case examples are provided to illustrate the utility of IN dosing. It is anticipated that the present review will prove useful for formulation scientists considering IN delivery as a delivery route.

Topical 0.5% nifedipine vs. lateral internal sphincterotomy for the treatment of chronic anal fissure: long-term follow-up

BACKGROUND

The aim of this study was to compare the efficacy of the local application of 0.5% nifedipine ointment vs. lateral internal sphincterotomy in the healing of chronic anal fissure.

PATIENTS AND METHODS

Sixty-four patients with symptomatic chronic anal fissures were randomly assigned to 0.5% nifedipine ointment (n=32) every 8 h for 8 weeks or lateral internal sphincterotomy (n=32). Both groups received stool softeners and fiber supplements and were assessed at 2, 4, 6, and 8 weeks. Long-term outcomes were determined after a median follow-up of 19 months (nifedipine group) and 20.5 months (lateral internal sphincterotomy group).

RESULTS

Complete healing at 8 weeks was achieved in 30 out of 31 patients (96.7%) in the nifedipine group and 32 out of 32 patients (100%) in the lateral internal sphincterotomy group (p=0.49). The overall healing rates at the end of follow-up were 28 out of 30 (93%) vs. 32 out of 32 (100%) in the nifedipine and sphincterotomy groups respectively (p=0.48). Two of the 30 patients in the nifedipine group relapsed whereas none in the sphincterotomy group did. Sixteen patients (50%) developed side effects in the nifedipine group, compared with six patients (18.7%) in the sphincterotomy group.

CONCLUSIONS

Topical application of 0.5% nifedipine ointment represents a new, promising, easily handled, effective alternative to lateral internal sphincterotomy.

Clinical pharmacokinetics and pharmacodynamics of glyceryl trinitrate and its metabolites

This review discusses the pharmacokinetics and pharmacodynamics of glyceryl trinitrate (nitroglycerin; GTN) pertinent to clinical medicine. The pharmacokinetics of GTN associated with various dose regimens are characterised by prominent intra- and inter-individual variability. It is, nevertheless, important to clearly understand the pharmacokinetics and characteristics of GTN to optimise its use in clinical practice and, in particular, to obviate the development of tolerance. Measurements of plasma concentrations of GTN and of 1,2-glyceryl dinitrate (1,2-GDN), 1,3-glyceryl dinitrate (1,3-GDN), 1-glyceryl mononitrate (1-GMN), and 2-glyceryl mononitrate (2-GMN), its four main metabolites, remain difficult and require meticulous techniques to obtain reliable results. Since GDNs have an effect on haemodynamic function, pharmacokinetic analyses that include the parent drug as well as the metabolites are important. Although the precise mechanisms of GTN metabolism have not been elucidated, two main pathways have been proposed for its biotransformation. The first is a mechanism-based biotransformation pathway that produces nitric oxide (NO) and contributes directly to vasodilation. The second is a clearance-based biotransformation or detoxification pathway that produces inorganic nitrite anions (NO(2) -). NO(2) - has no apparent cardiovascular effect and is not converted to NO in pharmacologically relevant concentrations in vivo. In addition, several non-enzymatic and enzymatic systems are capable of metabolising GTN. This complex metabolism complicates considerably the evaluation of the pharmacokinetics and pharmacodynamics of GTN. Regardless of the route of administration, concentrations of the metabolites exceed those of the parent compound by several orders of magnitude. During continuous steady-state delivery of GTN, for instance by a patch, concentrations of 1,2-GDN are consistently 2-7 times higher than those of 1,3-GDN, and concentrations of 2-GMN are 4-8 times higher than those of 1-GMN. Concentrations of GDNs are approximately 10 times higher, and of GMNs approximately 100 times higher, than those of GTN during sustained administration. The development of tolerance is closely related to the metabolism of GTN, and can be broadly categorised as haemodynamic tolerance versus vascular tolerance. Efforts are warranted to circumvent the development of tolerance and facilitate the use of GTN in clinical practice. Although this remains to be accomplished, it is likely that, in the near future, regimens will be developed based on a full understanding of the pharmacokinetics and pharmacodynamics of GTN and its metabolites.

The dilemma of immediate preoperative hypertension: to treat and operate, or to postpone surgery?

STUDY OBJECTIVE

To evaluate the efficacy and complications of immediate preoperative reduction of arterial blood pressure (BP) in patients with well-controlled hypertension but with diastolic blood pressure (DBP) between 110 and 130 mmHg on arrival at the operating room (OR).

DESIGN

Prospective, randomized, large-sample study.

SETTING

University-affiliated, 550-bed community hospital.

PATIENTS

989 patients with well-controlled hypertension, who were scheduled for surgery, and who had no previous myocardial infarction, unstable or severe angina pectoris, renal failure, pregnancy induced hypertension, left ventricular hypertrophy, previous coronary revascularization, aortic stenosis, preoperative dysrhythmias, conduction defects, or stroke.

INTERVENTIONS

Patients with DBP between 110 and 130 mmHg were randomly allocated to two groups: 400 patients in the control group and 589 patients serving as the study group. The control group had their surgery postponed and they remained in hospital for BP control, and the study patients received 10 mg of nifedipine intranasally delivered. The patients were observed for cardiovascular and neurological complications during the intraoperative period and over the first three postoperative days.

MEASUREMENTS AND MAIN RESULTS

The two groups were similar in age, gender, type of surgery, duration of anesthesia, and intraoperative fluid administration. There were no statistically significant differences in postoperative complications. The hospitalization time was considerable shorter in the study group than in the control group.

CONCLUSIONS

Immediate preoperative reduction of DBP with intranasal nifedipine is safe in patients with well-controlled arterial hypertension but they presented with severe to very severe hypertension for patients in the OR. We were able to avoid unnecessary surgery postponement and attendant costs.

Topical nifedipine with lidocaine ointment vs. active control for treatment of chronic anal fissure: results of a prospective, randomized, double-blind study

PURPOSE

Chronic anal fissure may be treated by chemical or surgical sphincterotomy. The aim of this study was to test the efficacy of local application of nifedipine and lidocaine ointment in healing chronic anal fissure.

METHODS

The study was performed according to a prospective, randomized, double-blind design. One hundred ten patients who gave informed consent were recruited. They received a clinical examination, a questionnaire to evaluate symptoms and pain, anorectal manometry, and anoscopy. Healing of anal fissure at Day 42 of therapy was defined as the primary efficacy variable of the study. Patients treated with nifedipine (n = 55) used topical 0.3 percent nifedipine and 1.5 percent lidocaine ointment every 12 hours for 6 weeks. The control group (n = 55) received topical 1.5 percent lidocaine and 1 percent hydrocortisone acetate ointment during therapy. Anal pressures were measured by recording resting and maximal voluntary contraction pressures at baseline and at Day 21. Long-term outcomes were determined after a median follow-up of 18 months.

RESULTS

Healing of chronic anal fissure was achieved after 6 weeks of therapy in 94.5 percent of the nifedipine-treated patients (P < 0.001) as opposed to 16.4 percent of the controls. Mean anal resting pressure decreased from a mean value +/- standard deviation of 47.2 +/- 14.6 to 42 +/- 12.4 mmHg in the nifedipine group. This represents a mean reduction of 11 percent (P = 0.002). Changes of maximal voluntary contraction in nifedipine-treated patients were not significant. No changes in mean anal resting pressure and maximal voluntary contraction were observed in the control group. We did not observe any systemic side effect in patients treated with nifedipine. After the blinding was removed, recurrence of the fissure was observed in 3 of 52 patients in the nifedipine group within 1 year of treatment, and 2 of these patients healed with an additional course of topical nifedipine and lidocaine ointment.

CONCLUSIONS

Our study clearly demonstrates that the therapeutic use of topical nifedipine and lidocaine ointment should be extended to the conservative treatment of chronic anal fissure.

Intranasal administration of naloxone by paramedics

INTRODUCTION

Naloxone is a medication that is frequently administered in the field by paramedics for suspected opioid overdoses. Most prehospital protocols, however, require this medication to be given to patients intravenously (i.v.) or intramuscularly (i.m.). Unfortunately, intravenous line placement may be problematic and time-consuming in chronic i.v. drug users. There may also be a delay in patient response to opioid reversal with i.m. absorption of naloxone. Additionally, routine use of needles in high-risk populations poses an increased risk of occupational blood exposures to paramedics.

OBJECTIVE

To prospectively test the effectiveness of intranasal (i.n.) naloxone administration by paramedics. This preliminary report summarizes the first month's experience in the city of Denver.

METHODS

Naloxone was first administered to patients found unconscious in the field using a nasal mucosal atomizer device (MAD). Patients were then treated using standard prehospital protocols, which included i.v. line placement and medications, if they did not immediately respond to i.n. naloxone. Time to patient response was recorded.

RESULTS

A total of 30 patients received i.n. naloxone in the field over a one-month period. Of these, 11 patients responded to either i.n. or i.v. naloxone. Ten (91%) patients responded to i.n. naloxone alone, with an average response time of 3.4 minutes. Seven patients (64%) did not require an i.v. in the field after response to i.n. naloxone.

CONCLUSIONS

Intranasal naloxone may provide a safe, rapid, effective way to manage suspected opioid overdoses in the field. Use of this route may decrease paramedic exposures to blood-borne diseases. The addition of i.n. naloxone administration to prehospital protocols should be considered as an initial therapy for suspected opioid abusers.

Inhalation therapy: new delivery systems

The objective of this article is to provide an overview of recent advances in inhalation drug delivery. Problems, advantages, limitations, and developments encountered by different inhalation devices and the agents used in these for the purpose of pulmonary delivery are discussed. A critical appraisal is presented and finally the future directions especially in research of the inhaled therapeutics and aerosols are described.

Conservative treatment of acute thrombosed external hemorrhoids with topical nifedipine

PURPOSE

This study was performed according to a prospective, randomized, open design. The aim was to test the efficacy of local application of nifedipine ointment in healing acute thrombosed external hemorrhoids.

METHODS

Ninety-eight patients who gave their informed consent were recruited; they received clinical examination and anoscopy. A questionnaire to evaluate symptoms, pain, and concurrent use of analgesics was administered. Patients treated with nifedipine (n = 50) used topical 0.3 percent nifedipine and 1.5 percent lidocaine ointment every 12 hours for two weeks. The control group, consisting of 48 patients, received topical 1.5 percent lidocaine ointment during therapy.

RESULTS

Results obtained were as follows: complete relief of pain in 43 patients (86 percent) of the nifedipine-treated group as opposed to 24 patients (50 percent) of the control group after 7 days of therapy (P < 0.01); oral analgesics were used by 4 patients (8 percent) in the nifedipine-treated group as opposed to 26 patients (54.1 percent) of the control group after 7 days of therapy (P < 0.01); and resolution of acute thrombosed external hemorrhoids was achieved after 14 days of therapy in 46 patients (92 percent) of the nifedipine-treated group, as opposed to 22 patients (45.8 percent) of the control group (P < 0.01). We did not observe any systemic side effect in patients treated with nifedipine.

CONCLUSIONS

Our study clearly demonstrates that the use of topical nifedipine, which at present is for treatment of cardiovascular disorders, is a reliable new option in the conservative treatment of thrombosed external hemorrhoids.

Topical Nifedipine(®) for conservative treatment of acute haemorrhoidal thrombosis

OBJECTIVE

The aim of this prospective, randomized trial was to test the efficacy of the local application of Nifedipine gel(®) in healing acute thrombosed haemorrhoids by relaxing the internal anal sphincter.

PATIENTS AND METHODS

Ninety patients who gave written informed consent were recruited; they received a clinical examination, anoscopy and a questionnaire to evaluate symptoms, pain and concurrent use of analgesics. Patients treated with Nifedipine (n=46) received topical 0.3% Nifedipine and 1.5% lidocaine gel every 12 h for 2 weeks. The control group, consisting of 44 patients, received topical 1.5% lidocaine and 1% hydrocortisone acetate gel during therapy.

RESULTS

The results were as follows: relief of pain in 84.7% in Nifedipine group as opposed to 50% of controls after 7 days of therapy (P < 0.01); oral analgesics were used by 8.6% of patients in the Nifedipine group as opposed to 54.5% of the control group (P < 0.01); resolution of thrombosed haemorrhoids occurred after 14 days of therapy in 91.3% of the Nifedipine-treated patients, as opposed to 45.4% of the controls (P < 0.01). No systemic side effects or significant anorectal bleeding were observed in patients treated with Nifedipine.

CONCLUSION

Our study clearly demonstrates that the use of Nifedipine, which at present is for treatment of cardiovascular disorders, should be extended to the conservative treatment of acute thrombosed haemorrhoids, using a topical application.

Nifedipine for local use in conservative treatment of anal fissures: preliminary results of a multicenter study

PURPOSE

This study was performed according to a prospective, randomized, double-blind, multicenter design. The aim was to test the efficacy of local application of nifedipine gel" in healing acute anal fissure by relaxing the internal anal sphincter.

METHODS

Two hundred eighty-three patients who gave informed consent were recruited; they received a clinical examination. A questionnaire to evaluate the symptoms and the pain was administered, and a proctoscopy and anorectal manometry were performed. Patients treated with nifedipine (n = 141) used topical 0.2 percent nifedipine gel every 12 hours for three weeks. The control group, consisting of 142 patients, received topical 1 percent lidocaine and 1 percent hydrocortisone acetate gel during therapy. Manometry was performed before and on Days 14 and 21. Anal pressures were measured by recording resting and squeeze pressures.

RESULTS

Results obtained were as follows: total remission from acute anal fissure was achieved after 21 days of therapy in 95 percent of the nifedipine-treated patients (P < 0.01), as opposed to 50 percent of the controls (P < 0.01), and previously elevated maximum resting anal pressures decreased from a mean value +/- standard deviation of 72.5 +/- 10.07 mmHg to 50.5 +/- 10.03 mmHg in the nifedipine group. This represents a mean reduction of 30 percent (P < 0.01). We also observed a significant decrease in squeeze pressures in nifedipine-treated patients (from a mean +/- standard deviation of 130.5 +/- 19.25 mmHg to 108.5 +/- 18.55 mmHg, a mean reduction of 16.8 percent; P < 0.01). No changes in anal pressures were observed in the control group. We did not observe any systemic side effect or significant anorectal bleeding in patients treated with nifedipine.

CONCLUSIONS

Our study clearly demonstrates that the therapeutic use of nifedipine, which at present is used only in cardiovascular pathologies, should be extended with local use to the conservative treatment of anal fissures.

Isosorbide aerosol: an option for the treatment of hypertensive crises

In this study the authors assessed the effectiveness and safety of isosorbide dinitrate aerosol administered through the oral mucosa in 30 adult patients who presented with a hypertensive crisis (mean arterial pressure > 130 mm Hg and evidence of target organ damage). The patients were given a first dose of 1.25 mg of aerosol when they were admitted to the hospital; a second dose was administered 15 minutes later if the mean arterial pressure had not decreased by > 15%. An electrocardiogram (ECG) was obtained for every patient immediately prior to and 30 minutes after administration of the medication. Nine patients (30%) had a good response with one dose, whereas 21 patients (70%) required a second dose. All 30 patients had a significant reduction of the arterial blood pressure (187+/-13 / 121+/-6.6 to 153+/-15.3 / 92.3+/-7.6 mm Hg; p<0.005) as well as of the mean arterial pressure (136.6+/-8 to 109.5+/-7 mm Hg; p<0.005) in a period of 30 minutes. No adverse effects, rebound hypertension, or severe hypotension were observed. These figures remained under control for 6 hours. Two of the patients had angina pectoris at admission and their ECG showed subepicardial ischemia, both of which disappeared with the medication. A second ECG appeared normal. A reduction of 14% in heart rate was obtained (95+/-15 to 82+/-14 beats per minute; p<0.005). These observations suggest that isosorbide dinitrate aerosol is an effective and safe alternative for the treatment of patients with hypertensive crises.

Traditional pharmacology and medicine in Africa. Ethnopharmacological themes in sub-Saharan art objects and utensils

Drawing from the general description that ethnopharmacology studies the human use of crude drugs and poisons in a traditional context, ethnopharmacological themes in native art can be defined as themes visualizing different features of traditional medicines and poisons, such as natural sources, methods of preparation, containers, usage and implements, target diseases and effects. This review documents that native African art objects and utensils are a goldmine of such ethnopharmacological themes by focusing on the following subjects: (a) objects related to the use of medicines (sources as well as tools for their collection, preparation and keeping); (b) objects related to the use of poisons (e.g. for ordeals, hunting and fishing); (c) objects related to the use of psychotropic agents (e.g. alcoholic beverages, kola nuts, smoking and snuffing materials); (d) pathological representations (e.g. treponematoses, leprosy, smallpox, swollen abdomen, scrotal enlargement, goiter and distorted faces); and (e) portrayals of certain types of treatment (e.g. topical instillations, perinatal care, and surgery). To avoid the impression that ethnopharmacology has little else to offer than armchair amusement, an epilogue outlines the medical relevance of this interdisciplinary science for Western and African societies.

Comparative biomembrane permeation of tacrine using Yucatan minipigs and domestic pigs as the animal model

Tacrine (THA), a centrally acting acetylcholine-esterase inhibitor, is presently administered perorally for the treatment of Alzheimer's disease (AD). However, its low bioavailablity (i.e., 17%) and short half-life (2-4 h) demand the search for alternative routes of administration. The primary objective of this study was to assess the potential of absorptive mucosae and skin as routes for improving the systemic delivery of THA. The Yucatan minipig, which has been used increasingly in biomedical research as a useful model for humans, and the domestic pig, which is available at low cost, were evaluated for their suitability as animal model. Permeation kinetics of THA across various absorptive mucosae (nasal, buccal, sublingual, and rectal) of both species of swine were studied in the hydrodynamically well-calibrated Valia-Chien permeation cells. For comparison, permeation through various intestinal segments (duodenum, jejunum, and ileum) was also measured. Results indicated that both species display similar permeation characteristics. However, the data obtained for the domestic pigs shows lower intra- and inter-animal variabilities than that of the Yucatan minipigs. The nasal mucosa was found to have the highest permeability, while the buccal mucosa had the lowest among the absorptive mucosae. The intrinsic permeabilities and diffusivity of THA across the four absorptive mucosae were not significantly different between species but lower than that for the intestinal segments for both species. Using dorsal skin as the model, the skin permeation of THA was also investigated and the results indicated that the domestic swine has a significantly higher skin permeability than the Yucatan minipig, with more than a 2-fold difference in intrinsic permeabilities. The intrinsic permeability, partition coefficient, and diffusivity for domestic pig skin are very similar to that for human cadaver skin. Considering the potential of bypassing the hepatic "first-pass" elimination, the absorptive mucosae may be useful routes for systemic delivery of THA to achieve improved bioavailability. With additional advantages of lower variability, ease of membrane excision, good accessibility, and lower cost, it is concluded that the domestic swine is a better animal model than the Yucatan minipig for preclinical studies on the systemic delivery of tacrine.